Description

A geographic information system (GIS) approach was used in conjunction with forest-plot data to develop an integrated moisture index (IMI) that is being used to stratify and help explain landscape-level phenomena in the four study areas. Several landscape features (a slope-aspect shading index, cumulative flow of water downslope, curvature of the landscape, and water-holding capacity of the soil) were used to create the IMI in the GIS. The IMI can be used to better manage forest resources where moisture is limiting and to predict how the resource will change under different forms of ecosystem management. In this study, the IMI was used to stratify the study areas into three moisture regimes: xeric, intermediate, and mesic. Of the 108 plots established across the four study areas (27 per study area), roughly a third fell into each of the three moisture classes. The proportion of land in each IMI class was similar among study areas. The Watch Rock site had the highest proportion area in the mesic class, while Bluegrass Ridge had the highest proportion of land in the xeric class. Among treatment areas within each study area, the distribution of IMI classes was similar, so that treatment effects can be attributed to the treatments rather than a priori landscape variation. Analysis of IMI by vegetation plot revealed that these plots well represent the entire treatment areas.